The gunman in the assassination attempt of Donald Trump searched online for events of both the former president and Joe Biden and saw the Pennsylvania campaign rally where he opened fire last month as a “target of opportunity”, a senior FBI official said on Wednesday. Thomas Matthew Crooks, who shot at Trump from a nearby roof before being killed by a Secret Service counter-sniper, did extensive research for an attack before the shooting and had looked at any number of events or targets, including the current and former president, said Kevin Rojek, the special agent in charge of the FBI’s Pittsburgh field office. The new details were disclosed as FBI officials, in the latest in a series of briefings about the investigation, revealed that they had yet to uncover a motive for the 13 July attack in Butler, Pennsylvania, despite conducting nearly 1,000 interviews. “We have a clear idea of mindset, but we are not ready to make any conclusive statements regarding motive at this time,” Rojek said.